title: Production of a variant of beta-lactamase II with selectively decreased cephalosporinase activity by a mutant of Bacillus cereus 569/H/9.
abstract: 1. Mutants of Bacillus cereus 569/H/9 have been screened in a search for strains that synthesize variants of beta-lactamase II. 2. One of these mutants (strain 569/H/9/1) produces a beta-lactamase II-like enzyme that shows a selective decrease in cephalosporinase activity. 3. beta-Lactamase II from strain 569/H/9/1 has been purified to apparent homogeneity and its kinetic properties have been examined. This enzyme resembles the parent beta-lactamase II in its relative activity with benzylpenicillin as substrate when Zn(II) is replaced by other metal ions, but differs detectably from the parent enzyme in its isoelectric point.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001409:Bacillus cereus / Q000201:enzymology*; D002413:Cations, Divalent; D002510:Cephalosporinase / Q000302:isolation & purification*; D055598:Chemical Phenomena; D002621:Chemistry; D007527:Isoenzymes / Q000302:isolation & purification*; D007700:Kinetics; D009154:Mutation; D010405:Penicillinase / Q000302:isolation & purification; D001618:beta-Lactamases / Q000302:isolation & purification*
chemical_list: D000596:Amino Acids; D002413:Cations, Divalent; D007527:Isoenzymes; D002510:Cephalosporinase; D010405:Penicillinase; D001618:beta-Lactamases